This invention relates to a near field presence detection device provided for monitoring an area around a mouth of a reading member, in particular a card reading member, said device comprises a presence detector having a transmitter and a receiver, said transmitter and receiver being provided to operate with a carrier frequency above 18 KHz in said area, said detector being provided to detect a change of field impedance due to a foreign object placed within said area and to generate a detection signal thereupon, said detector being further provided to generate a preliminary alarm signal if a signal level of said detection signal generated by said detector exceeds a predetermined threshold range, said detector being connected to a verification unit provided for determining upon receipt of said preliminary alarm signal if said preliminary alarm signal subsists within a predetermined period (t2−t1) and for producing an effective alarm signal if said preliminary alarm signal subsists within said predetermined period (t2−t1), (from U.S. Pat. No. 6,390,367).
Such a detection device is known and for example used in automatic teller machines (ATMs). It is well known that ATMs are subjected to burglary attempts and attacks of various kinds aiming like skimming devices, Lebanese loops, etc.
ATMs are commonly and increasingly used to carry out many everyday transactions which do not require human supervision. As such transaction may involve transfer or dispense of valuable media, such as banknotes or payment orders, ATMs may present a target of fraud.
To make use of a conventional ATM, a user is first required to insert a card into the mouth of the card reader to the ATM fascia, the card serving as an identification token. The user must then confirm his or her identity by, for example, entering a personal code (PIN) associated with the card, but known only by the user and by the operative system. If an unauthorized individual wishes to gain access to an individual's account and thus to make unauthorized withdrawals of funds, it is necessary to both obtain the data stored on the card and gain knowledge of the appropriate personal code. Thus, potential targets for fraud include the card reader and the data input or capture device used for entry of the personal code. Methods which have been used in attempts to execute such fraud include fitting false interfaces to the fascia of an ATM in order to intercept the relevant data as it is being communicated to the ATM. For example, an additional magnetic card reader may be placed into, before or on the mouth of the existing card reader, so that the information stored on the magnetic strip of the card may be read, and consequently copied, as the card is inserted into the ATM. The thus intercepted data may then be used to construct a fraudulent card.
An other example of commonly used fraudulent device is the well known Lebanese loops which captures the original card of a user. A camera placed in a close proximity of the ATM registers the personal code input by the authorized user. When the transaction is ended, the user is not able to receive back his card. Generally the user does not worry about this card capture because he or she thinks about a defiance of the ATM. The defrauder has just to retrieve the card blocked in the ATM and read the personal code registered by the camera in order to get in his possession all the necessary data for using the magnetic card.
These fraud techniques are efficient because traditional sensors placed for protection of these ATMs against burglaries are too or not enough sensible to detect those fraud techniques.
The prior art describes fraud detection devices provided with sensors or means for producing a continuous alarm signal upon detection of a foreign object placed in or around the ATM. U.S. Pat. No. 4,514,623 discloses an ATM adapted to reject a foreign object introduced in the mouth. A blocking member prevents the transport of introduced objects and only enables such transport when sensors signal the presence of an object which meets established criteria. A drawback of this device is that it is unable to detect subtle fraud like Lebanese loops placed in the mouth in order to fraud the data of the user. The Lebanese loop will not be detected by the sensors since the loop is not presented to the sensors.
EP-A-0 965 960 discloses another protection device which comprises a loudspeaker and a microphone. The loudspeaker emits white noise which is picked up by the microphone. The detected signal constitutes an acoustic signature which changes if the ATM is tampered with, for example, by inserting some fraudulent mechanism into the ATM to intercept banknotes before they reach the output slot of the ATM. If any such change is detected then an alarm can be risen. This fraud detection system however presents a major drawback. Indeed, it is unusable because the detectors are too much sensible to background noise of the street, like talking people, car noises, advertiser noises, or climatic conditions like hard rain, grail and the like.